From 6a2c659b31879d269c39374757968561b689bf03 Mon Sep 17 00:00:00 2001
From: Bruce Momjian <bruce@momjian.us>
Date: Sun, 25 Sep 2005 03:18:16 +0000
Subject: [PATCH] [ Patch to 7.4.X.]

In several places PL/Python was calling PyObject_Str() and then
PyString_AsString() without checking if the former had returned
NULL to indicate an error.  PyString_AsString() doesn't expect a
NULL argument, so passing one causes a segmentation fault.  This
patch adds checks for NULL and raises errors via PLy_elog(), which
prints details of the underlying Python exception.  The patch also
adds regression tests for these checks.  All tests pass on my
Solaris 9 box running HEAD and Python 2.4.1.
---
 src/pl/plpython/plpython.c | 21 ++++++++++++++++++---
 1 file changed, 18 insertions(+), 3 deletions(-)

diff --git a/src/pl/plpython/plpython.c b/src/pl/plpython/plpython.c
index 332927013a5..80b60a4777f 100644
--- a/src/pl/plpython/plpython.c
+++ b/src/pl/plpython/plpython.c
@@ -29,7 +29,7 @@
  * MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
  *
  * IDENTIFICATION
- *	$Header: /cvsroot/pgsql/src/pl/plpython/plpython.c,v 1.41.2.1 2004/01/04 00:14:55 momjian Exp $
+ *	$Header: /cvsroot/pgsql/src/pl/plpython/plpython.c,v 1.41.2.2 2005/09/25 03:18:16 momjian Exp $
  *
  *********************************************************************
  */
@@ -561,6 +561,8 @@ PLy_modify_tuple(PLyProcedure * proc, PyObject * pltd, TriggerData *tdata,
 		if (plval != Py_None && !tupdesc->attrs[atti]->attisdropped)
 		{
 			plstr = PyObject_Str(plval);
+			if (!plstr)
+				PLy_elog(ERROR, "function \"%s\" could not modify tuple", proc->proname);
 			src = PyString_AsString(plstr);
 
 			modvalues[i] = FunctionCall3(&proc->result.out.r.atts[atti].typfunc,
@@ -847,6 +849,8 @@ PLy_function_handler(FunctionCallInfo fcinfo, PLyProcedure * proc)
 	{
 		fcinfo->isnull = false;
 		plrv_so = PyObject_Str(plrv);
+		if (!plrv_so)
+			PLy_elog(ERROR, "function \"%s\" could not create return value", proc->proname);
 		plrv_sc = PyString_AsString(plrv_so);
 		rv = FunctionCall3(&proc->result.out.d.typfunc,
 						   PointerGetDatum(plrv_sc),
@@ -2117,7 +2121,9 @@ PLy_spi_execute_plan(PyObject * ob, PyObject * list, int limit)
 		char	   *sv;
 
 		PyObject   *so = PyObject_Str(list);
-
+		if (!so)
+			PLy_elog(ERROR, "function \"%s\" could not execute plan",
+							PLy_procedure_name(PLy_last_procedure));
 		sv = PyString_AsString(so);
 		PLy_exception_set(PLy_exc_spi_error,
 						  "Expected sequence of %d arguments, got %d. %s",
@@ -2166,6 +2172,9 @@ PLy_spi_execute_plan(PyObject * ob, PyObject * list, int limit)
 			if (elem != Py_None)
 			{
 				so = PyObject_Str(elem);
+				if (!so)
+					PLy_elog(ERROR, "function \"%s\" could not execute plan",
+									PLy_procedure_name(PLy_last_procedure));
 				sv = PyString_AsString(so);
 
 				/*
@@ -2693,7 +2702,13 @@ PLy_traceback(int *xlevel)
 	else
 		vstr = "Unknown";
 
-	estr = PyString_AsString(eob);
+	/*
+	 * I'm not sure what to do if eob is NULL here -- we can't call
+	 * PLy_elog because that function calls us, so we could end up
+	 * with infinite recursion.  I'm not even sure if eob could be
+	 * NULL here -- would an Assert() be more appropriate?
+	 */
+	estr = eob ? PyString_AsString(eob) : "Unknown Exception";
 	xstr = PLy_printf("%s: %s", estr, vstr);
 
 	Py_DECREF(eob);